Stent coating with a CD31 agonist improves the biocompatibility of coronary stents in vivo

Abstract

The ideal stent coating should be able to reduce the local inflammatory reaction, as drug-eluting stents (DES) do but should also favour the rapid endothelialisation as bare-metal stents (BMS) do. We aimed at combining the anti-inflammatory and pro-endothelialisation properties in a novel stent coating inspired from CD31, a transmembrane receptor critically involved in the physiologic regulation of leukocyte activation and endothelial integrity within the circulation. A CD31-mimetic peptide was covalently immobilized on BMS stents (Multilink ® ) by click chemistry. Uncoated stents, and everolimus-eluting made of exactly the same material (Xience ® ) were used as controls. The 3 types of stents ( n = 6/type) were implanted in the coronary arteries of farm pigs. Aspirine (75 mg) and ticagrelor (180 mg) were administered daily, per os. Seven days later, the stented coronary segments were carefully excised, fixed and cut longitudinally. Their luminal surface was metallized and evaluated blindly by scanning electron microscopy ( Fig. 1 ). As shown in the figure, CD31-coated and BMS were entirely covered by a smooth endothelial cell layer whereas endothelial cells on DES were scant and non-junctional. A few round-shaped leukocytes were found adherent onto the CD31-coated and DES stents whereas BMS consistently presented areas covered by multiple spread-shaped (activated) leukocytes. Immobilization of CD31 agonist improves the biocompatibility of coronary stents by combining the beneficial features of BMS (complete endothelialization within 7 days) and DES (reduced inflammatory reaction) without their respective drawbacks. The use of this biomimetic coating may serve to foster a more physiologic integration of coronary stents within the arterial wall.